I'm a Professor of Biomedical Engineering, Computer Science, and Biostatistics in the Institute of Genetic Medicine at Johns Hopkins University's School of Medicine. From 2005-2011 I was the Horvitz Professor of Computer Science and Director of the Center for Bioinformatics and Computational Biology at the University of Maryland, College Park. Before joining UMD, I was at The Institute for Genomic Research, where I sequenced the genomes of many bacteria, including those used in the 2001 anthrax attacks. At TIGR I was part of the Human Genome Project and the co-founder of the influenza virus sequencing project (which is when I first learned of the anti-vaccine movement). My research group develops software for DNA sequence analysis, and our (free) software is used by scientific laboratories around the globe. I did my B.A. and M.S. at Yale University, and my Ph.D. at Harvard University, and I have published over 200 scientific papers. Follow me on Facebook or Twitter (@stevensalzberg1), or just subscribe to my alternate blog, http://genome.fieldofscience.com.

Last week a scientific paper appeared that reported that eating genetically modified (GM) corn causes cancer in rats. Specifically, the scientists fed Roundup Ready® corn, or maize, to rats for two years, and reported that both females and males developed cancer and died at higher rates than controls. [Update: this study was retracted, see this link]

This is very surprising. If GM corn causes cancer, why aren’t Americans “dropping like flies,“ as one scientist asked? We’ve been eating MonsantoMonsanto‘s Roundup Ready® corn for over a decade, even if most of us aren’t aware of it. But our rates of cancer haven’t increased more than Europeans, who eat far less GM corn. Maybe the effect is limited to rats – in which case we should also have seen dramatic increases in cancer in lab rats. But we haven’t seen that either. So what’s wrong? The best way to find out is to read the paper, which I did. It turns out to be a very badly designed study, and the report itself omits many crucial details that may (and probably do) completely invalidate the findings. The scientists leading the study have a strongly biased agenda and a conflict of interest, which they failed to reveal. I’ll explain below, but meanwhile this study has already been taken up by politicians as proof (proof!) that GMO crops are harmful. As Forbes blogger Tim Worstall explained, this paper is more politics than science.

Let’s look at the study itself, which was led by Gilles-Eric Seralini (more on him below) and published last week in Food and Chemical Toxicology. (A copy of the full paper is here.) The authors studied 200 rats for 2 years, dividing them into 10 group of 20 rats each. The test rats were fed a variety of diets:

Non-GM corn comprising 33% of the diet (this was the control group).

Roundup Ready corn comprising 11%, 22%, or 33% of the food.

Roundup Ready corn that had been treated with Roundup during cultivation.

Non-GM corn but with Roundup itself added to the rats’ water.

So what happened? Well, in some groups, the rats got more cancer than controls. But not always. In fact, the authors had to cherry-pick their own data to support their conclusions. One major problem is that only 10% of the rats were controls – 10 male, 10 female. The study’s main claim is that rates of cancer were significantly higher in the rats fed GM corn. Martina Newell-McGloughlin from UC Davis, in an interview with Discovery News, said

“The type of statistical analysis they used is really a type of fishing expedition. One individual referred to it as ‘fantasy statistics.’ “

Another major problem is that there’s no dosage effect. In other words, if Seralini is right and GM food is bad for you, then more of it should be worse. But the study’s results actually contradict this hypothesis: rats fed the highest levels of GM corn lived longer than rats fed the lowest level. A third problem, as Discovery News and other sources reported, is that the rats used in this study are a special laboratory strain that is highly prone to cancer. Perhaps most damning, though, is the fact that rats fed Roundup directly had the longest survival times. As Seralini’s own Figure 1 shows, the longest-living rats in the entire study, out of all the conditions, where those that drank Roundup in their water. These rats outlived the control rats. Yum! Maybe Perrier should start selling Roundup-enhanced spring water? Seralini and colleagues struggle to explain the internal contradictions in their study. They write,

“Interestingly, in the groups of animals fed with the NK603 [Roundup Ready corn] without R[oundup] application, similar effects with respect to enhanced tumor incidence and mortality rates were observed.”

This tortured English is their way of admitting that rats did worse (“similar effects”) when fed GM corn that was grown without Roundup. They don’t want to admit that this result contradicts their central hypothesis. The study was designed to fail: the sample sizes (10 rats in each group) are so small that all the results are likely just due to chance, and none of the differences are meaningful. It’s exceedingly unlikely that the Roundup in the rats’ water made them live longer, just as it’s unlikely that Roundup Ready corn had any effect on the incidence of cancer.

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The burden of proof should be on companies like Monsanto to show that GMO products are safe for human consumption over the long term – not on independent researchers to prove that these products are hazardous to our health. Monsanto is very clear on where they stand on the matter. From their own website: “There is no need for, or value in testing the safety of GM foods in humans. “

Should every company need to run years of studies to determine that a product is safe? I suspect we would all be living in tents with no technology at all if this were the case. There never has been a valid reason to suspect that GMO has health impacts. I’m not saying we shouldn’t study it but yes the burden is on you, the one raising the out-of-left-field claims, that has the burden.

“It’s unfortunate that Monsanto’s behavior has been used as an excuse to give all GMOs a bad name.” Great point- Monsanto is a scourge that spoils the concept of GMO.

At the same time you imply that because the FDA sanctioned Monsanto to do their own tests (not surprising when you look at who runs the FDA)- and ended up doing 90 day studies, it proves it is safe?! How dare this small independent group not perform a test with higher interval but far less scale then a immensely large corporation.

Another major problem is that there’s no dosage effect. In other words, if Seralini is right and GM food is bad for you, then more of it should be worse. I presume this is intellectual dishonesty or your part? As you are very astute and educated, and now far more about medicine than me. Bt fortunately as you say, any person can go on line and research. Now it appears that high levels of toxidity can get turned off by the immune system….I am not suggesting this is the case here…but you are blatantly lying to say that The law of toxicity is a simple more = more Illness. You know that is not always the case. Alos the report doesnt highlight round up ready…it highlights GM food… you slated the round up ready based results and then dammed the whole paper on this…Then to add more sloppy reporting, you state the truth that this is not a big enough study group to be a taken as useful scientifically. So which is it? you can’t fight both sides of the argument? On personal note I agree with highlighting stupid Pseudo science and discrediting it.

My God Forbes is biased. I wish I had time to enumerate all the clumsy attempts to obfuscate in this forbes article but Ill just point out one: “the groups of animals fed with the NK603 [Roundup Ready corn] without R[oundup] application, similar effects with respect to enhanced tumor incidence and mortality rates were observed.” Blog implies they disproved themselves by finding that GMO-only rats had similar mortality to Roundup-only rats. This would mean that GMOs caused the same enhanced tumor incidence as ingesting herbicide. This supports their hypothesis. Did you really think you could inveigle a little “switcheroo” and forbes readers would be too stupid to notice? I’m disgusted. This is “bad science”.

Cancer is less a disease than a condition existing in the whole human body. Cancer would be almost unheard of if no devitalized food or meats were eaten since cancer cannot exist where there is a pure bloodstream. Avoid meat in all forms including dairy. Meat is a dead matter, low in minerals, and produces uric acid in excess which is a waste product. The incidence of cancer is in direct proportion to the amount of meat and meat products in the diet. Regular meat eaters (especially red meat) have a higher probability of getting cancers, such as colon cancer and prostate cancer. Digestion of meat uses trypsin and chymotrypsin, which are two critical enzymes in the human body to allow the immune system to kill cancer cells. Vegetable proteins do not use up those enzymes. Cancer patient should not eat anything that is not building the immunity system or killing cancer cells. Meat does not contribute to curing the cancer, so meat is should be avoided by cancer patients. There are plenty of foods that help cure cancer, so there is no need to eat meat. Pancreatin enzymes can be destroyed by contact with acids. Diet comprised mostly of processed refined foods and meats may result in lower pH that depletes these enzymes in the human body. Cancer cells metabolize foods very inefficiently and produce acidic wastes. This extra acidity can further lower the pH levels in an already acidic environment for pancreatin enzymes. The lower pH level also enables the cancer to spread by using acid dissolved normal cells as its food source. This strongly acidic lower pH environment, especially local to the cancer is the primary reason that cancer does not normally heal on its own. The colon should be relatively clear during a cancer treatment so that the body can absorb as many nutrients as possible. All foods like meat which ferment in the bowel should be avoided to prevent the accumulation of fecal matter in the colon. The hormones in meat like artificial sex hormone widely used in cattle – Diethylstilbestrol cause cancer of the uterus, breast and other reproductive organs. Dangerous residues of stilbestrol are in 85% of all the meat sold in North America. This is the main reason why fifteen countries around the world now refuse to import meat produced in the US; and twenty one countries have a total ban on the use of stilbestrol in food production or processing. When chemical preservatives and color enhancers are ingested, they cause the body to produce nitrosamines which cause cancer of the liver, stomach, brain, bladder, kidneys and several other organs. Nitrates and nitrites are heavily added to meat during processing. Runoff of nitrates and nitrites from fields sprayed with chemical fertilizers get into drinking water and cause cancer. can lead to cancer. If the digestive system is weak, digestion of meat could produce toxins in blood.

Though devitalized, processed, and sugared food can also cause cancer even in vegetarians. People, communities and groups who consume less meat have less cancer. Seventh-day Adventists, who eat little or no meat, suffer far less from cancer than the average meat-eating American. High protein diet of Americans is linked to the high incidence of cancer in the US. Anyone who does not eat meat, eats only good food, and does all he can to protect his liver, may never get cancer. The second solution is to introduce the appropriate calciums into the body since the body uses calcium as the chief alkalinizer of all body fluids including the intra-cellular fluids. Cancers and tumors can only exist in a predominantly lower pH (acidic) environment caused by a diet rich in dairy foods, meats, grain products, sweets and strong condiments such as black pepper. This is always accompanied by an acute lack of living fruits and vegetables. High acidity destroys bones, because the body has to use alkalizing minerals from bones to keep the blood pH from dropping into the acid range. Lactobacillus acidophilus is a friendly organism which helps the body fight disease and restores health. Acidophilus kills the harmful bacteria strain of E. coli in the intestinal tract. Acidophilus breaks milk sugar down into lactic acid. Bacteria which produce putrefaction and gas in the intestines cannot live in lactic acid. Acidophilus also has the unique ability to help the body synthesize, or manufacture all of the ‘B’ vitamins in the system. This makes it especially valuable since there is literally a host of agents which destroy B vitamins. A few are antibiotics, birth control pills, eating sugar and refined foods and drinking coffee. A diet high in red meat will destroy the beneficial bacteria, due to the concentration of antibiotics and steroids given to the animals before they are slaughtered. Cancer is fundamentally involved with mal-utilization of protein. Oncologists generally agree that the actual cause of death in cancer patients is cachexia, a condition of severe weight loss and wasting associated with protein mal-absorption. In fact cancer cells are able to grow by making the amino acids of protein available for their growth at the expense of the body as a whole. Meat, especially red meat, being the most readily assimilable protein, becomes a banquet for cancer cells. Emphasizing the use of plant sources of vegetable protein such as legumes and beans that contain cancer-fighting compounds should be a prominent part of an anti-cancer diet. The most damaging evidence that meat is a major cause of cancer are studies of people who went into spontaneous remission solely because of a change in their diet. These people almost universally went from a cooked food, meat-centered diet and gave up their meat, their dairy products and their refined sugar and switched to a raw food vegetarian diet, and by simply changing diets their bodies were able to cure their cancer.

If all the GMO issues are so good then why will Monsanto and other manufacturers not allow a clean and clear study by any third parties Globally? That is the rub! Anything short of that we should remain suspect. It’s time for a public forum with total transparency by allowing third party scientific studies. The manufacturers of any food or food based products should have to be mandated to have every study before it enters our food stream and blood stream, because having worked directly with some of these groups who are controlling our world I know first hand they do have agenda’s that may not be in our best interest.

U.S.Food and Drug Administration’s (FDA) own research shows that the cancer causing arsenic added to the chicken feed ends up in the chicken meat where it is consumed by humans. California added to its list of cancer-causing chemicals an additive commonly used in processed beverages like Coca Cola, Pepsi etc – 4-methylimidazole (4-MI) – a byproduct formed during the production of caramel color. Sodium Nitrate (aka Sodium Nitrite) – a preservative, coloring, and flavoring commonly added to bacon, ham, hot dogs, luncheon meats, smoked fish, and corned beef – causes various types of cancer. Butylated hydroxyanisole (BHA) and butylated hydrozyttoluene (BHT) are used to preserve common household foods including cereals, chewing gum, potato chips, vegetable oils and canned foods – form cancer-causing reactive compounds in human body. Propyl Gallate – preservative, often used in conjunction with BHA and BHT in meat products, chicken soup base, and chewing gum causes cancer Acesulfame-K is a new artificial sweetener used in baked goods, chewing gum, and gelatin desserts causes cancer Food Colorings like Blue 1, 2 is used in beverages, candy, baked goods; Red 3 used to dye cherries, fruit cocktail, candy, and baked goods; Green 3 used in candy and beverages; Yellow 6 is added to beverages, sausage, gelatin, baked goods, and candy; cause various type of cancer. Potassium Bromate used as an additive to increase volume in some white flour, breads, and rolls causes cancer. - Nalliah Thayabharan

I for one am not surprised that GM corn alone could create more cancer in rats The corn itself was given a protein that inhibits it’s own life span without the roundup product. However despite all of the food fights going on lately I am more concerned with super germs. The GM foods using the protein above will create disease resistant plants that have been with us for millions of years. So what if we change the climate in which they grow? Because to create super disease resistant plants is to create super insects and super germs. If you look at this this is how you create a super germ ok? So? For me? I am afraid of the near future and super diseases that even Monsanto doesn’t count on.